System and method for detection enhancement programming

ABSTRACT

A system and method of enabling detection enhancements selected from a plurality of detection enhancements. In a system having a plurality of clinical rhythms, including a first clinical rhythm, where each of the detection enhancements is associated with the clinical rhythms, the first clinical rhythm is selected. The first clinical rhythm is associated with first and second detection enhancements. When the first clinical rhythm is selected, parameters of the first and second detection enhancements are set automatically. A determination is made as to whether changes are to be made to the parameters. If so, one or more of the parameters are modified under user control.

CLAIM OF PRIORITY

This patent application is a division of U.S. patent Ser. No.11/379,742, filed on Apr. 21, 2006, which is a continuation of U.S.patent Ser. No. 10/025,958, filed on Dec. 18, 2001, now issued as U.S.Pat. No. 7,532,931, which is a continuation of U.S. patent applicationSer. No. 09/378,029, filed on Aug. 20, 1999, now issued as U.S. Pat. No.6,493,579, the specifications of which are hereby incorporated byreference.

FIELD OF THE INVENTION

The present invention is related to implantable cardioverterdefibrillator therapy, and more particularly to a system and method fordisplaying and selecting detection enhancements within a cardioverterdefibrillator.

BACKGROUND INFORMATION

Detection enhancements are used in implantable cardioverterdefibrillator therapy to reduce the incidence of inappropriate shocks.In the past, defibrillators were only rate derivative. If the patient'sheart rate crossed over the prescribed rate, a shock was delivered tothe heart. Experience showed that the heart could pass through theprescribed rate for a variety of reasons, only some of which warrantedshocking the heart. For instance, the heart could beat faster duringexercise, or because the person was excited, or even due to atrialarrhythmia. None of these warrant shock therapy.

Detection enhancements are sets of rules for determining when to delivershock therapy. These rules may, for instance, look not only at thechange in rate but also at the source of the arrhythmia, at thesuddenness of onset or at the stability of the heart beat.

In the past, detection enhancements were treated as separate items on alaundry list of possible detection enhancements. The language used todescribe the features was often a reflection of the programming codeused to implement the features. Such an approach was confusing tophysicians. As a result, physicians either ignored the enhancements orstruggled with programming the detection enhancements into the patient'sdefibrillator.

What is needed is a system and method for displaying and selectingdetection enhancements within a cardioverter defibrillator whichaddresses these deficiencies.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a system and method ofenabling detection enhancements selected from a plurality of detectionenhancements is described. In a system having a plurality of clinicalrhythms, including a first clinical rhythm, where each of the detectionenhancements is associated with the clinical rhythms, the first clinicalrhythm is selected. The first clinical rhythm is associated with firstand second detection enhancements. When the first clinical rhythm isselected, parameters of the first and second detection enhancements areset automatically. A determination is made as to whether changes are tobe made to the parameters. If so, one or more of the parameters aremodified under user control.

According to another aspect of the present invention, a system andmethod of programming one or more detection enhancements into adefibrillator is described. In a system having a plurality of clinicalrhythms, including a first clinical rhythm, where each of the detectionenhancements is associated with the clinical rhythms, the first clinicalrhythm is selected. The first clinical rhythm is associated with firstand second detection enhancements. When the first clinical rhythm isselected, parameters of the first and second detection enhancements areset automatically. A determination is made as to whether changes are tobe made to the parameters. If so, one or more of the parameters aremodified under user control. The defibrillator is then programmed toperform the first and second detection enhancements as a function of theparameters.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, where like numerals refer to like components throughoutthe several views:

FIG. 1 illustrates an implantable cardioverter defibrillator within ashock therapy system;

FIG. 2 illustrates a method of selecting detection enhancements from aplurality of possible detection enhancements and of modifying parametersassociated with the selected detection enhancements;

FIG. 3 illustrates one embodiment of the system of FIG. 1;

FIG. 4 illustrates display showing a representative three zoneconfiguration;

FIG. 5 illustrates detection enhancements availability within zones of amulti-zone configuration;

FIG. 6 illustrates AFib Rate Threshold and Stability interaction;

FIG. 7 illustrates representative Onset, Stability and AFib Ratecombinations and the suggested therapy;

FIG. 8 illustrates representative Onset and Stability combinations andthe suggested therapy;

FIG. 9 illustrates Sustained Rate Duration in relation to inhibitorenhancements;

FIG. 10 illustrates detection enhancement details for VT-1 zone;

FIG. 11 illustrates rhythm discrimination available per zone inmulti-zone configurations;

FIGS. 12 and 13 illustrate one embodiment of pre-selected parametervalues suitable for detection enhancements by clinical rhythm;

FIG. 14 illustrates detection enhancement details for VT-1 zone;

FIG. 15 illustrates a display emphasizing VT zone parameters within amulti-zone configuration; and

FIG. 16 illustrates detection enhancement details for VT zone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings which form a part hereof,and in which is shown by way of illustration specific embodiments inwhich the invention may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from the scope of the present invention.

Some portions of the detailed descriptions which follow are presented interms of algorithms and symbolic representations of operations on databits within a computer memory. These algorithmic descriptions andrepresentations are the means used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of steps leading to a desiredresult. The steps are those requiring physical manipulations of physicalquantities. Usually, though not necessarily, these quantities take theform of electrical or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like. It should be borne in mind, however, thatall of these and similar terms are to be associated with the appropriatephysical quantities and are merely convenient labels applied to thesequantities. Unless specifically stated otherwise as apparent from thefollowing discussions, it is appreciated that throughout the presentinvention, discussions utilizing terms such as “processing” or“computing” or “calculating” or “determining” or “displaying” or thelike, refer to the action and processes of a computer system, or similarelectronic computing device, that manipulates and transforms datarepresented as physical (electronic) quantities within the computersystem's registers and memories into other data similarly represented asphysical quantities within the computer system memories or registers orother such information storage, transmission or display devices.

FIG. 1 illustrates an implantable shock therapy system. Shock therapysystem 10 includes a defibrillator 12, a power supply 14 and aprogrammer 20. Power supply 14 is connected to defibrillator 12 andsupplies power to defibrillator 12.

In one such embodiment, defibrillator 12 includes a telemetry system 16for communicating with programmer 20. In addition, defibrillator 12supplies the requisite therapy to the heart via leads 18.

In one embodiment, programmer 20 includes an input device 22 such as akeyboard or mouse, a display 24 and telemetry system 26. Featuresselected or programmed by physicians into programmer 20 are communicatedthrough telemetry to defibrillator 12, where they control shock andpacing therapy applied to the patient's heart. Detection enhancementsare just some of the features programmed in this manner by thephysician.

As noted above, in the past detection enhancements were treated asseparate items on a laundry list of possible detection enhancements. Thelanguage used to describe the features was often a reflection of theprogramming code used to implement the features. Such an approach wasconfusing to physicians. As a result, physicians either ignored theenhancements or struggled while programming the detection enhancementsinto the patient's defibrillator.

As a response to this problem, programmer 20 includes control logicwhich allows the physician to program all appropriate enhancements by aprocess of selection. In one embodiment, the physician checks boxes thatdescribe the patient's arrhythmia (e.g., Atrial Fibrillation or SinusTachycardia). In another embodiment, symbols representative of thearrhythmia are displayed to be selected by the user. For instance, ifthere are two detection enhancements that protect against sinustachycardia, a symbol labeled “sinus tachycardia protection” isdisplayed.

In one embodiment, the physician uses input device 22 to indicate theselected arrhythmia and programmer 20 programs defibrillator 12 toperform the underlying detection enhancements. In one such embodiment,programmer 20 uses artificial intelligence to set values of parameterswithin each of the desired detection enhancements. These values may bedefault values, or can be calculated as a function of patient or therapyparameters already established in programmer 20. In one expert systemembodiment, a set of rules establish the values set for parametersprogrammed automatically by programmer 20. Such a system is describedbelow.

A system which programs detection enhancements by simply checkingclinical rhythms and letting the programmer do the rest may not beflexible enough to meet the varying demands of the real world. Toaddress this, in one embodiment, programmer 20 includes control logicwhich allows the physician to manipulate parameters associated with thedetection enhancements selected on the basis of clinical rhythms. Thisprovides the experienced physician the ability to manipulate the valuesof parameters associated with particular detection parameters, whileletting the less sophisticated user rely on the expertise of theengineers and physicians who designed the defibrillator system.

One method of selecting detection enhancements from a plurality ofpossible detection enhancements and of modifying parameters associatedwith the selected detection enhancements is shown in FIG. 2. Programmer20 is programmed to include a number of different clinical rhythms. Eachclinical rhythm is associated with one or more detection enhancements.At 30, the physician selects one or more of the available clinicalrhythms. In one embodiment, programmer 20 displays the availableclinical rhythms on display 24 so that the physician can select one ormore clinical rhythms through input device 22. In another embodiment,the physician may enter the desired clinical rhythms by typing ordictating labels corresponding to the desired rhythm into input device22.

Once the one or more clinical rhythms has been selected, control movesto 32, where programmer 20 identifies the detection enhancementsassociated with the selected clinical rhythms and sets parametersassociated with the identified detection enhancements. Control moves to34, where a determination is made as to whether the physician wishes tomodify one or more of the detection enhancement parameters. This may bedone, for example, by directly querying the physician on display 22, orby presenting a set of options which includes a “Modify parameters”button or icon.

If a determination is made that the physician does not wish to modifyone or more of the detection enhancement parameters, control moves to38, where the detection enhancement parameters are programmed intodefibrillator 12.

If a determination is made that the physician does wish to modify one ormore of the detection enhancement parameters, control moves to 36, andthe physician enters or modifies the desired values. Control then movesto the 38, where the detection enhancement parameters are programmedinto defibrillator 12.

One embodiment of a system 10 used to deliver shock therapy to a heartis shown in FIG. 3. In FIG. 3, shock therapy system 50 includes adefibrillator 52, a programmer 54 and a communications link 56.Communications link 56 transfers data between defibrillator 52 andprogrammer 54. Embodiments of communications link 56 include wired,wireless, optical and other forms of communications.

In one such embodiment, programmer 54 includes selection module 58,parameter modification module 60 and communication module 62. Selectionmodule 58 displays the available clinical rhythms. Each clinical rhythmis associated with one or more detection enhancements. Selection module58 also includes a user interface which allows a user to select one ormore to the clinical rhythms.

Parameter modification module 60 receives the selected clinical rhythmfrom first control logic 58, stores parameters related to the associateddetection enhancements, determines if the user wishes to modify theparameters, and, if the user modifies the parameters, stores themodified parameters.

Communication module 62 programs defibrillator 52 to perform theassociated detection enhancements as a function of the storedparameters. Module 62 also is connected to selection module 58 in orderto display data captured by defibrillator 52.

In one embodiment, a user interface is designed for system 10 to providea “layering” effect. That is, the top screen is designed to provide easyactivation of the detection enhancements by displaying clinical rhythmdiscrimination features that the physician may wish to program.Parameters associated with the selected detection enhancements areseeded with a suggested set of nominal values; the physician can chooseto accept these values or can change any or all values as desired. Ifthe physician chooses to change the suggested values, access is given toan underlying screen where the specific detection enhancements arelisted, and the programming values are accessible. With this dual-layerapproach, system 10 provides the flexibility to the physician to eitheruse proven, preselected values or to change the values to patientspecific settings.

As noted above, detection enhancements are used to add specificity torate and duration detection criteria. In one embodiment, enhancementscan be programmed to delay or inhibit therapy, to bypass therapyinhibition, or to bypass a sequence of ATP therapy in favor of shocktherapy. Some of the available detection enhancements include V Rate >ARate, AFib Rate Threshold, Stability, Onset, Shock if Unstable andSustained Rate Duration (SRD).

The V Rate >A Rate enhancement is used to deliver therapy anytime theventricular rate is greater than the atrial rate. It can also be used tobypass the Onset, Stability, and/or AFib Rate Threshold parameters'decision to inhibit therapy.

The AFib Rate Threshold enhancement is programmed to inhibit ventriculartherapy if the atrial rhythm is fast. The Stability parameter isprogrammed to inhibit therapy delivery if the ventricular rhythm isunstable. Onset is programmed to inhibit therapy if the patient's heartrate increases gradually. The Shock if Unstable parameter is programmedto bypass ATP therapy and deliver shock therapy if the analysis of theventricular rhythm is declared to be unstable. The Sustained RateDuration (SRD) parameter enables the pulse generator to override theOnset, Stability, or AFib Rate Threshold parameters' decision to inhibittherapy if the high rate continues throughout the programmed timeperiod.

In one embodiment, if any of the following features, V Rate >A Rate,AFib Rate Threshold, Brady Mode programmed to DDD(R), DDI(R), DVI(R),VDD(R), or AAI(R), Electrogram Storage Enabled for the atrial electrode,or Atrial Rate EGM trace selected are programmed, the pulse generatorwill respond to atrial sensing whether an atrial lead is implanted ornot. If an atrial lead is not implanted, atrial data will be erroneous.

The atrial rate may be used to both 1) inhibit therapy in the presenceof atrial fibrillation (AFib) or atrial flutter, and 2) to bypass Onset,Stability, and/or AFib Rate Threshold as inhibitors if programmed On andthe ventricular rate is faster than the atrial rate.

The V Rate >A Rate (ventricular rate greater than atrial rate) parametercan be programmed to bypass inhibitors (Onset, Stability, and/or AFibRate Threshold) and initiate therapy in the event that the ventricularrate is faster than the atrial rate. It can be programmed On or Off.Analysis is made by comparing the average rate of the last 10ventricular intervals prior to the end of duration to the average rateof the last 10 atrial intervals prior to the end of duration and afterthe third fast ventricular interval. If fewer than 10 atrial intervalsare available, then the intervals available will be used to calculatethe average atrial rate. If the average ventricular rate is greater thanthe average atrial rate by at least 10 min⁻¹, the ventricular rate isdeclared to be faster than the atrial rate (indicated as True on theEpisode Detail report) and therapy will be initiated. If the ventricularrate is not greater than the atrial rate (indicated as False on theEpisode Detail report), then therapy may continue to be inhibited.

If therapy is inhibited, the V Rate >A Rate analysis continues untileither the ventricular rate is greater than the atrial rate or the otherenhancements indicate therapy treatment, at which time therapy will beinitiated.

Atrial rate detection is used to inhibit therapy in the event that theunderlying cause of a moderately high ventricular rate is due toventricular response to fibrillation in the atrium. This is accomplishedby comparing the atrial rate to the preprogrammed AFib Rate Threshold.If the atrial rate is greater than the AFib Rate Threshold, therapy willbe withheld until the atrial rate drops below the AFib Rate Threshold,or, if programmed On, the V Rate >A Rate is True, or the Sustained RateDuration timer expires. Programmable values for the AFib Rate Thresholdare Off or 200-400 min⁻¹.

When the AFib Rate Threshold is programmed separately from the Stabilityparameter, a determination is made that the atrial rate is above theAFib Rate Threshold in the following manner. At initiation ofventricular tachyarrhythmia detection, atrial analysis begins. Eachatrial interval is classified as faster or slower than the AFib RateThreshold interval. When 6 of the last 10 intervals are classified asfaster than the AFib Rate Threshold, the device declares atrialfibrillation to be present. Therapy will be withheld, and the atrialrate will continue to be examined; as long as 4 of 10 intervals remainclassified as fast, atrial fibrillation continues to be present. Whenprogrammed with Stability the ventricular rhythm is also considered inthe decision.

If AFib Rate Threshold and Stability are both programmed On, the devicewill analyze both parameters to determine if therapy is to be deliveredor withheld. If the atrial rate is greater than the AFib Rate Thresholdand the ventricular rhythm is classified as unstable, the ventricularrhythm is declared to be due to atrial fibrillation.

The atrial rate is declared to be above the AFib Rate Threshold in themanner discussed above. Ventricular stability is then checked and, ifunstable, therapy will be inhibited. In the event that therapy is notdelivered, the atrial rate will continue to be examined; as long as 4 of10 intervals remain classified as fast, atrial fibrillation continues tobe present. Therapy is inhibited until the atrial rate drops below theAFib Rate Threshold, the ventricular rhythm becomes stable, or ifprogrammed On, V Rate >A Rate is true or Sustained Rate Duration timesout. An illustration of AFib Rate Threshold and Stability interaction isshown in FIG. 6.

In one embodiment, the device will initiate therapy when a stable rhythmis declared; and will initiate therapy for an unstable rhythm when it isdetermined that the atrial rate is less than the AFib Rate Threshold.

If the AFib Rate Threshold, Stability, and Onset parameters are allprogrammed On, to initiate therapy the rhythm must have a sudden onsetand either the ventricular rate must be stable or the atrial rate mustbe less than the AFib Rate Threshold. If the detection enhancement VRate >A Rate is programmed On and is determined to be True, it takesprecedence over all other inhibitor enhancements.

The Onset enhancement measures the rate of transition in ventricularrhythm from slow rates to tachycardia. It is intended to differentiatephysiologic sinus tachycardias, which typically begin slowly, frompathologic tachycardias, which typically begin abruptly. With Onsetenabled, the device inhibits therapy in the lowest tachycardia rate zoneif the rate increase is gradual. Programmable values for Onset are Offor 9-50% or 50-250 ms.

The Onset enhancement is measured using ventricular rate only and may beprogrammed as a percentage of cycle length, or as an interval length inms. It is limited to the lowest zone of a multizone configuration. Theselected Onset value represents the minimum difference that must existbetween intervals that are below the lowest programmed rate thresholdand intervals that are above the lowest programmed rate threshold. Thepulse generator performs Onset calculations (even when it is programmedOff) for all episodes except induced episodes, and stores the measuredOnset results from a two-stage calculation in therapy history. Thisstored data (in ms and %) is useful in programming an appropriate Onsetvalue.

When a detection window becomes satisfied (episode declared and memoryallotted for history data storage), the pulse generator beginscalculating for sudden onset in a two-stage sequence.

The first stage measures the intervals prior to the start of the episodeand locates the pair of adjacent intervals (pivot point) where the cyclelength decreased the most. If the decrease in cycle length is equal toor greater than the programmed Onset value, the first stage declaresonset to be sudden.

The second stage then compares additional intervals; if the differencebetween the average interval before the pivot point and 3 out of thefirst 4 intervals following the pivot point is equal to or greater thanthe programmed Onset threshold, the second stage declares onset to besudden.

If both stages declare the rhythm sudden, therapy will be initiated. Ifeither stage indicates a gradual onset, initial therapy will beinhibited in the lowest zone; then therapy will be delivered only if therate accelerates to a higher zone, information from the atrial leaddetermines that the ventricular rate is faster than the atrial rate (VRate >A Rate programmed On), or the Sustained Rate Duration (SRD) timerexpires.

Stability analysis is used to distinguish unstable (irregular)ventricular rhythms from stable (regular) ventricular rhythms. This isaccomplished by measuring the degree of variability of the tachycardiaR-R intervals. This degree of variability, when used by itself, mayallow the device to distinguish conducted atrial fibrillation (which mayproduce greater R-R variability) from monomorphic VT (which is typicallystable). It also may be used to differentiate MVTs (which are paceterminable) from polymorphic VTs and VF (which are typically not paceterminable). Based on the patient's needs, the physician may choose toprogram Stability as an inhibitor to prevent therapy for atrialfibrillation, or use stability analysis to direct the type of therapy tobe delivered (Shock if Unstable).

The stability analysis algorithm calculates R-R interval differences.These differences are calculated throughout Duration, and an averagedifference is also calculated. When Duration expires, rhythm stabilityis evaluated by comparing the current average difference to theprogrammed Stability and Shock if Unstable thresholds. If the averagedifference is greater than the programmed thresholds, the rhythm isdeclared unstable. Independent thresholds are available for theStability (to inhibit) or Shock if Unstable functions; both cannot beprogrammed in the same zone. Programmable values for Stability Analysiscan be Off or 6-120 ms.

In one embodiment, the pulse generator performs stability calculationsfor all episodes (even when Stability is programmed Off) and stores theresults in therapy history. This stored data is useful in selecting anappropriate stability threshold.

The Stability parameter can be used to identify rapid rhythmsoriginating in the atrium, such as atrial fibrillation, that may resultin unstable rhythms in the ventricle whose rate exceeds the lowest ratethreshold and which should not be treated. If a rhythm is declaredstable when Duration expires, programmed therapy will be delivered. Ifthe rhythm is declared unstable, the parameter will render a decision towithhold therapy. This is intended for rhythms originating in the atriumthat may result in unstable rhythms in the ventricle whose rate exceedsthe lowest rate threshold. At the end of initial Duration, if atachycardia is declared unstable and therapy is inhibited, the pulsegenerator continues to evaluate for stability on each new detectedinterval. It will evaluate for stability as long as the zone's detectionwindow remains satisfied, or until the V Rate >A Rate declares theventricular rate greater than the atrial rate, or the Sustained RateDuration (SRD) timer has expired (if programmed On). If the rate becomesstable before V Rate >A Rate is True or the SRD timer has expired, theprogrammed therapy is initiated immediately.

In one embodiment, Stability can be inhibited only in the lowest zone ofa two- or three-zone configuration; it may be used in conjunction withother detection enhancements.

In one embodiment, Stability can be programmed to Shock If Unstable. Inthis programming mode, the stability analysis helps determine if ATPtherapy should be bypassed in preference for the first programmed shocktherapy (which may be low or high energy) for the zone. Dynamicventricular arrhythmias such as polymorphic VT or VF may be sensed at arate lower than the highest rate threshold and can be classified asunstable. Since the sensed rhythm may be detected in a lower zone inwhich ATP may be programmed, the stability analysis may be used to skipover the programmed ATP therapies and instead provide shocks to thepatient. Stability is evaluated on each detection/redetection cycle,including evaluation between bursts of an ATP scheme. Once a shock hasbeen delivered in an episode, the Shock If Unstable function no longeraffects therapy selection.

The Shock If Unstable feature may be used only in the VT zone of atwo-zone configuration or three-zone configuration. It cannot beprogrammed in a two-zone configuration if Stability or Onset is alreadyprogrammed On, or if Post-shock Stability or AFib Rate Threshold isprogrammed On.

When Stability is programmed to inhibit, it may be combined with theOnset parameter to provide even greater specificity in characterizingarrhythmias. The enhancements can be programmed such that to initiatetherapy, both Onset And Stability must indicate to treat, or such thatif either Onset Or Stability indicates to treat, therapy is delivered(see FIGS. 7 and 8 for representative Onset, Stability and AFib Ratecombinations and the suggested therapy).

If the combination programmed is Onset And Stability, therapy isinhibited if either parameter indicates that therapy should be withheld;that is, the rhythm is gradual Or unstable (the And condition to treatis not satisfied). If the combination programmed is Onset Or Stability,therapy is inhibited immediately at the end of Duration only if bothparameters indicate that therapy should be withheld; that is, the rhythmis gradual and unstable (the Or condition to treat is not satisfied). Ineither case, therapy is initiated only if the And/Or conditions to treatare satisfied. When these two combinations (And/Or) are used inconjunction with Sustained Rate Duration (SRD), and the And/Orconditions are not satisfied, therapy is inhibited until V Rate >A Rateis True or SRD times out.

Sustained Rate Duration (SRD) allows the programmed therapy to bedelivered when a tachycardia is sustained for a programmed period oftime beyond Duration, but the programmed therapy inhibitors (AFib RateThreshold, Onset, and/or Stability) indicates to withhold therapy. FIG.9 illustrates SRD in relation to the inhibitor enhancements. It is notused in conjunction with Shock If Unstable. In one embodiment,programmable values for SRD are Off or 10 to 60 seconds.

SRD is used only when an inhibitor enhancement is programmed On. If aninhibitor is withholding therapy delivery and the Rate criterion in thelowest zone is maintained, the SRD timer begins at the end of Duration.If the detection window in the lowest zone is maintained for theprogrammed SRD period, the programmed therapy will be delivered at theend of the SRD period. If the rate accelerates to a higher zone and theDuration for the higher zone expires, therapy is initiated in that zonewithout waiting for SRD to time out. If SRD is programmed Off, an SRDtimer will not start when Duration expires.

In one embodiment, detection enhancements are available in only certainzones of a multi-zone configuration. One such embodiment is shown inFIG. 5.

A representative three zone configuration is shown in FIG. 4. In theembodiment shown in FIG. 4, system 10 includes up to threetachyarrhythmia zones (labeled as VT-1, VT, and VF). In one suchembodiment, such as is shown in FIG. 4, each zone is identified ondisplay 24 with its label 70 and its rate threshold 72. In theembodiment shown in FIG. 4, label 70 and its associated rate threshold72 are displayed within a zone rate bar 74. In addition, a detectionsummary for each zone is displayed within detection button 76 for thatzone and a therapy summary for each zone is displayed within therapybutton 78 for that zone.

In one embodiment, the user accesses the detection parameters for a zoneby selecting the respective detection button 76 and accesses the therapyparameters for a zone by selecting the respective therapy button 78. Theuser selects the rate threshold value in order to change the ratethreshold for that zone. And the number of tachyarrhythmia zones can bemodified by selecting one of the number buttons beneath the “# Zones”label.

In one embodiment, if parameter settings have changed but have not yetbeen programmed into the pulse generator, hatch marks (////) will appearin the summary area. When the values are programmed, the hatch marksdisappear.

A subset of zone configuration information is displayed when the systemsummary and quick check screens are visible, which allows a shortcut tothe detection and/or therapy parameters screens. (Only presentlyprogrammed values are displayed; it does not display changed data thathas not yet been programmed into the device nor hatch marks.) In oneembodiment, the user selects a shortcut icon to navigate to the TachyParameters screen, which displays detailed information. If a shortcuticon appears dim, it indicates that a change to the number of zones hasnot been programmed; thus a shortcut is not available to the parameterscreens.

A brady therapy summary 80 is also visible in FIG. 4. This area displaysthe normal and post-shock bradycardia modes and rates. Additionalbradycardia parameter settings may be viewed and changed by selectingthe brady summary button when a shortcut icon is visible, or the BradyParameters tool. Depending on which toolbox screen is visible, thissummary button may show just the rate/zone bar or may include additionalinformation as is shown in FIG. 4.

Toolbox 82 displays various features depending on the chosen toolboxbutton. The features allow interaction with the pulse generator as wellas a review of data in pulse generator memory. Only one tool may beselected at a time. (In one embodiment, the System Summary tool isselected when the application is initially accessed. However, if anepisode is in progress at initial interrogation, the EP Test screen willbe displayed.)

In the embodiment shown in FIG. 4, windows contain information relevantto a particular function. They may include names of pulse generatorparameters and functions, value boxes to accommodate value changes,buttons to open additional windows, and buttons to cancel changes orclose the window. To remove the window from the display, select thebutton that initiates activity or select the Close or Cancel button.

Message windows are used to provide feedback during communicationsessions. Some require action as indicated in the window beforecontinuing the session, while others simply relay information withoutrequiring further action or show status of an activity. Many messagewindows have a Cancel or Close button; select the desired button tocancel the action being performed as explained in the message and/orclose the window.

In the embodiment shown in FIG. 4, ECG display 84 is always visible. ECGdisplay 84 shows real-time surface ECG traces, as well as real-timeelectrograms (EGMs) and event markers, which are useful in ascertainingsystem performance. In one such embodiment, a 20-second snapshot of theECG trace, electrograms, and markers can be printed automatically; whenthe cursor is positioned over the ECG display the cursor changes to acamera icon; click the left trackball key to “capture” the trace. Theprinted trace shows 10 seconds before and 10 seconds after the moment ofcommand.

In one embodiment, annotated event markers identify certain intrinsiccardiac and device-related events, and provide information such assensed/paced events, decision of detection criteria, and therapydelivery. The markers are displayed on ECG display 84.

In one embodiment, real-time electrograms can be transmitted from thepace/sense or shocking electrodes to evaluate lead system integrity suchas lead fractures, insulation breaks, or dislodgments.

The number of zones, the zones' rate thresholds, and values fordetection, redetection, and detection enhancement parameters can beprogrammed from the Zone Configuration display in FIG. 4 in thefollowing manner.

First, select Tachy Parameters button 86 from toolbox 82 to display thezone configuration area and the selected zone's parameters. Next, changethe number of zones by selecting the desired number (1, 2, or 3) fromthe #Zones column. The zone configuration will display the selectednumber of zones with hatch marks overlaying the new zones, which havenot been programmed into the device yet. Third, change the ratethreshold using either select box 72 from zone/rate bar 74 or via thezone's detection button 76. If a zone's detection button 76 has beenselected, the initial and redetection parameters 88 are displayed. FIG.4 illustrates the initial and redetection parameters associated with theVT-1 zone, while FIG. 15 illustrates the initial and redetectionparameters associated with the VT zone. Detection enhancement rhythmdiscrimination categories 90 (see FIGS. 4 and 15) are displayed as wellfor those zones in which enhancements are available.

Next, change any of the desired initial or redetection parameters. Inone embodiment, hatch marks overlay the zone's detection button 76 untilthe changed parameters have been programmed into the pulse generator.Note: As parameter values are changed, the information icon and/or stopsign icon may appear at the top of the main application screen to informof potential parameter interactions. Modify parameters as required toget around these objections. More information on parameter interactioncan be found in “System and Method for Detecting and DisplayingParameter Interactions,” filed herewith.

Next, select the magnifying-glass icon to display enhancement parameterdetails. Detection enhancement details for VT-1 zone are shown in FIGS.4, 10 and 14. Detection enhancement details for VT zone are shown inFIGS. 15 and 16.

As noted above, detection enhancement parameters can be more easilyprogrammed by identifying the type of rhythm discrimination desired andassociating the clinical rhythms with particular detection enhancements.In one embodiment, the types of clinical rhythms include: atrialtachyarrhythmia, sinus tachycardia, and polymorphic VT. FIG. 11illustrates rhythm discrimination available per zone in multi-zoneconfigurations.

When a rhythm discrimination is selected, preselected values aredisplayed for the parameters that are suitable for discriminating thatrhythm (see FIGS. 12 and 13). From a zone's detection screen, detectionparameters can be turned On by selecting the Detection Enhancements Onor Off value box, or by selecting the individual rhythm types (see FIGS.10, 14 and 16).

To access the detection enhancement parameters, one would select thevalue box in the Change column next to the text “Detection Enhancements”in a zone's detection window. If Select On is chosen, the boxes next tothe type of rhythm discriminations will be checked. If Select Off ischosen, the boxes remain unchecked.

One can select individual discrimination types. To select or deselectindividual discrimination types, select the box next to thediscrimination type to check or uncheck the box.

One can also view detection enhancement window 92 shown in FIGS. 10, 14and 16. In one embodiment, detection enhancement windows 92 can beviewed by selecting magnifying-glass icon 94 of FIGS. 4 and 15. Therespective individual parameters and values are displayed for whicheverdiscrimination type is selected. Parameter values can then be adjustedfrom this window. The discrimination types are automatically checked andunchecked according to the changes made in the enhancement window.

Window 92 is closed when the parameters values are as desired.

A shock therapy system such as system 10 provides the ease of use ofselecting detection enhancements as a function of clinical rhythm while,at the same time, providing layers of complexity, so that for those thatare used to programming the specific parameters can do so. Newer usersbenefit from the expertise of the designers by letting the underlyingexpert systems set the appropriate parameters. Experienced users benefitby only having to modify the entries that differ from those preset bythe expert system.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiment shown. This application isintended to cover any adaptations or variations of the presentinvention. Therefore, it is intended that this invention be limited onlyby the claims and the equivalents thereof.

What is claimed is:
 1. A method for delivering shocks to a heart, themethod comprising: displaying one or more predetermined clinical rhythmsfor selection; receiving a clinical rhythm selected from the displayedone or more predetermined clinical rhythms; identifying one or moredetection enhancements associated with the selected clinical rhythm, theone or more detection enhancements each being a set of rules fordetermining when to deliver one or more of the shocks; and settingdetection enhancement parameters associated with the identified one ormore detection enhancements; and programming the detection enhancementparameters into a device to perform the identified one or more detectionenhancements.
 2. The method of claim 1, wherein setting the detectionenhancement parameters comprises setting the detection enhancementparameters to stored detection enhancement parameter values.
 3. Themethod of claim 1, wherein setting the detection enhancement parameterscomprises determining whether to receive a modification to the detectionenhancement parameters.
 4. The method of claim 3, wherein setting thedetection enhancement parameters further comprises receiving themodification to the detection enhancement parameters through a userinterface.
 5. The method of claim 1, wherein the shocks compriseventricular shocks, and programming the detection enhancement parametersinto the device comprises programming the detection enhancementparameters into a defibrillator to perform at least one of delaying adelivery of one of the shocks, inhibiting a delivery of one of theshocks, bypassing an inhibition of a delivery of one of the shocks, andbypassing another therapy in favor of a delivery of one of the shocks.6. The method of claim 5, wherein identifying the one or more detectionenhancements comprises selecting a detection enhancement includingdelivering one of the shocks if a ventricular rate is greater than anatrial rate.
 7. The method of claim 5, wherein identifying the one ormore detection enhancements comprises selecting a detection enhancementincluding inhibiting a delivery of one of the shocks if the atrialrhythm is fast.
 8. The method of claim 5, wherein identifying the one ormore detection enhancements comprises selecting a detection enhancementincluding inhibiting a delivery of one of the shocks if the ventricularrate is unstable.
 9. The method of claim 5, wherein identifying the oneor more detection enhancements comprises selecting a detectionenhancement including inhibiting a delivery of one of the shocks if aheart rate increases gradually.
 10. The method of claim 5, whereinidentifying the one or more detection enhancements comprises selecting adetection enhancement including delivering one of the shocks if ananalysis of the ventricular rhythm is determined to be unstable.
 11. Themethod of claim 5, wherein identifying the one or more detectionenhancements comprises selecting a detection enhancement includingdelivering one of the shocks if a high heart rate continues throughout aprogrammed time period.
 12. The method of claim 1, wherein displayingthe one or more predetermined clinical rhythms comprises displaying oneor more tachyarrhythmia zones.
 13. The method of claim 12, whereindisplaying the one or more tachyarrhythmia zones comprises displayingone or more of atrial tachyarrhythmia, sinus tachycardia, polymorphicventricular tachyarrhythmia, and ventricular fibrillation.
 14. A cardiacshock therapy system comprising: means for displaying a plurality ofpredetermined clinical rhythms for selection; means for receiving aselection of one or more clinical rhythms from the plurality ofpredetermined clinical rhythms; means for identifying one or moredetection enhancements associated with the selected one or more clinicalrhythms from a plurality of predetermined detection enhancements; meansfor determining detection enhancement parameters associated with theidentified one or more detection enhancements; and means for programmingthe detection enhancement parameters into a device to perform theidentified one or more detection enhancements.
 15. The system of claim14, wherein the means for determining parameters comprises means fordetermining whether to receive a modification to the parameters.
 16. Thesystem of claim 14, wherein the means for displaying and the means forreceiving comprise a user interface means.
 17. The system of claim 16,wherein the user interface means comprises means for presenting aplurality of arrhythmia zones each associated with one or more detectionenhancements of the plurality of predetermined detection enhancements.18. The system of claim 17, wherein the user interface means comprisesmeans allowing for changing a number of the arrhythmia zones in theplurality of arrhythmia zones.
 19. The system of claim 17, wherein themeans for presenting the plurality of arrhythmia zones comprises meansfor displaying rate threshold values each of which is associated withone of the plurality of arrhythmia zones and for allowing for changingof the rate threshold value for the one of the plurality of arrhythmiazones.
 20. The system of claim 14, wherein the means for determiningparameters also comprises a further user interface means including:means for displaying a detection parameter summary associated with theone of the plurality of arrhythmia zones and allowing for modificationsof the detection parameters associated with that one of the plurality ofarrhythmia zones; and means for displaying a therapy parameter summaryassociated with the one of the plurality of arrhythmia zones andallowing for modifications of the therapy parameters associated withthat one of the plurality of arrhythmia zones.